Liner for use in processing chamber

ABSTRACT

A container for use in a processing chamber to lessen the amount of contaminant particles found within the chamber after processing. The container fits closely within the chamber and includes ports for a gas conduit and a vacuum conduit. The container may be locked to the chamber through a locking mechanism and a recess in the container. The container may be guided into the chamber with a plurality of chamfers. The container may be used in inductively coupled plasma chambers, electron cyclotron resonance chambers, and chambers capable of receiving microwaves.

This application is a continuation of application Ser. No. 09/317,629filed on May 25, 1999, now U.S. Pat. No. 6,234,219, the entirety ofwhich is hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to the processing of work pieces used insemiconductor fabrication. More particularly, the present inventionrelates to a reusable container, or liner, for use in a work pieceplasma processing chamber.

BACKGROUND OF THE INVENTION

A plasma is a collection of electrically charged and neutral particles.In a plasma, the density of negatively-charged particles (electrons andnegative ions) is equal to the density of positively-charged particles(positive ions). Plasma generation may be conducted by applying power toelectrodes in a chamber of a reactor. In diode or parallel platereactors, power is applied to one electrode to generate a plasma. Intriode reactors, power is typically applied to two of three electrodesto generate a plasma.

In radio frequency (RF) plasma generation, for a diode reactor, asinusoidal signal is sent to an electrode of a pair of electrodes.Conventionally, a chuck or susceptor is the powered electrode. Examplesof parallel plate reactors include the 5000MERIE from Applied Materials,Santa Clara, Calif.

A plasma source material, which typically includes one or more gases,such as, for example, argon, silane (SiH₄), oxygen, TEOS, diethylsilane,and silicon tetrafluoride (SiF₄), is directed to an interelectrode gapbetween the pair of electrodes. The amplitude of the RF signal must besufficiently high for a breakdown of plasma source material. In thismanner, electrons have sufficient energy to ionize the plasma sourcematerial and to replenish the supply of electrons to sustain a plasma.The ionization potential, the minimum energy needed to remove anelectron from an atom or molecule, varies with different atoms ormolecules.

In a typical triode reactor, three parallel plates or electrodes areused. The middle or intermediate electrode is conventionally located inbetween a top and bottom electrode, and thus two interelectrode cavitiesor regions are defined (one between top and middle electrode and onebetween middle and bottom electrode). The middle electrode typically hasholes in it. Conventionally, both the top and bottom electrode arepowered via RF sources, and the middle electrode is grounded. Examplesof triode reactors are available from Lam Research, Fremont, Calif., andTegal Corporation Ltd., San Diego, Calif.

Parallel plate and triode reactors generate capacitively coupledplasmas. These are conventionally “low density” plasmas (ion-electrondensity of less or equal to 10¹⁰ ions-electrons per cm³) as comparedwith high-density (also known as “hi density”) plasmas which aregenerated by systems such as electron cyclotron resonance (ECR) andinductively coupled plasma (ICP). For ICP systems, an inductive coil(electrode) is conventionally driven at a high frequency using an RFsupply. The inductive coil and RF supply provide a source power, or toppower, for plasma generation. In ECR systems, a microwave power source(for example, a magnetron) is used to provide a top power. Both ICPand-ECR systems have a separate power supply known as bias power orbottom power, which may be employed for directing and accelerating ionsfrom the plasma to a substrate assembly or other target. In either case,voltage that forms on a susceptor or chuck (also known as the directcurrent (DC) bias), is affected by the bottom power (RF bias); whereas,current is affected by the top power.

DESCRIPTION OF THE RELATED ART

It has been known that control of particulate contamination isimperative for cost effective, high-yielding manufacture of VLSIcircuits. This control is by necessity increasing with increasinglysmaller lines, feature sizes and critical dimensions being designed onsuch circuits. Contamination particles cause incomplete etching of workpieces such as reticules or wafers in spaces between lines, thus leadingto an unwanted electrical bridge. Further, contamination particles mayinduce ionization or trapping centers in gate dielectrics or junctionsor in reticule areas which will be used in semiconductor fabrication,leading to electrical failure of a fabricated part.

The major sources of contamination particles are personnel, equipment,and chemicals. For example, people, by shedding of skin flakes, createparticles which are easily ionized and can cause defects. It isestimated that particles sized from less than 0.01 micrometers to 200micrometers and above should be of concern during the processing ofsemiconductors. “Clean rooms” are typically used for semiconductormanufacture, and through filtering and other techniques, attempts aremade to prevent entry of particles with sizes of 0.03 micrometers andlarger. It is virtually impossible, however, to keep particles smallerthan 0.03 micrometers out of a clean room.

To address the problem of semiconductor contamination, a StandardMechanical Interface (SMIF) system was devised. The SMIF system providesa small volume of still, particle-free air, with no internal source ofparticles, for transporting wafers. SMIF designs are discussed in U.S.Pat. Nos. 5,752,796 (Muka) and 5,607,276 (Muka et al.).

While the SMIF system is useful for preventing particle contaminationduring transport of the wafers, it is wholly ineffective at preventingcontamination during processing of the wafers. The SMIF containers areused during the transport of the wafers, but are removed when the wafersare placed in processing chambers for wafer processing.

Particulate contamination builds up within work piece processingchambers, such as a plasma processing chamber. This build up ofcontaminants must be cleansed from the processing chambers periodically.This entails considerable time and effort and requires the removal ofthe processing chamber from a production line. This, in turn, causeslost production time and increases costs.

There is, thus, a need in the industry for a low cost and effectivemethod and apparatus for reducing the need to periodically clean workpiece processing chambers, such as a plasma processing chamber.

SUMMARY OF THE INVENTION

The present invention provides a removable container which is insertedinto a processing chamber and in which the work piece processing iscarried out. The container has at least one side and a base, as well asan ingress and egress for the work piece. The container further includesone or more ports located in the side which connect with ports of theprocessing chamber which provide gasses or other materials used inprocessing. The container is made of materials allowing the container tohave an effective life at least as long as the required processing,preferably allowing the container to be reused a number of times. Alocking mechanism may be included to lock the container within thechamber.

The present invention also provides a system for processing asemiconductor work piece. The system includes a processing chamber and aremovable container having the characteristics noted in the precedingparagraph. In one aspect of the invention, the processing chamber is aplasma processing chamber.

The present invention further provides a method of processing asemiconductor work piece in which the work piece is provided within acontainer, the container being removably inserted in a work pieceprocessing chamber, with the processing being accomplished inside thecontainer.

The invention may be used to process any work piece associated withsemiconductor fabrication including, but not limited to, reticules,masks, leads, wafers, and packages.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is perspective view of a conventional plasma processing chamber.

FIG. 2 is a top view of the processing chamber of FIG. 1.

FIG. 3 is a cross-sectional view taken along line 2—2 of FIG. 2 of thechamber of FIG. 1 and a container constructed in accordance with anembodiment of the present invention.

FIG. 4 is a perspective view showing the container of FIG. 3 and thechamber of FIG. 1.

FIG. 5 is a top view of the chamber of FIG. 1 showing the interior ofthe chamber.

FIG. 6 is a partial cross-sectional view of a chamber and containerconstructed in accordance with another embodiment of the presentinvention.

FIG. 7 is a top view of a container constructed in accordance withanother embodiment of the present invention.

FIG. 8 is a partial cross-sectional view of a chamber and container ofFIG. 7.

FIG. 9 is a cross-sectional view of a chamber and of a containerconstructed in accordance with another embodiment of the presentinvention.

FIG. 10 is a close-up view of a locking mechanism taken within circle XIof FIG. 3.

FIG. 11 is a cross-sectional view of a chamber and of a containerconstructed in accordance with another embodiment of the presentinvention.

FIG. 12 is a cross-sectional view of a chamber and of a containerconstructed in accordance with another embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following description, the invention is described in connectionwith a plasma processing chamber. However, this is merely illustrativeof one environment of use for the invention and the invention is not tobe considered as limited to that environment. Also, the invention can beused with other work piece processing chambers. In addition, theinvention is described with reference to a reticule, which is but oneexample of a work piece which can be processed using the invention.

Referring now to the drawings, where like numerals designate likeelements, there is shown in FIG. 1 a reticule processing chamber 10. Theprocessing chamber 10, which is shown as being generally cylindrical inshape, is an inductively coupled plasma processing chamber and includesan inductive coil 16 as an electrode wrapped around a side surface 14thereof. The chamber 10 further includes a door 18 and an under surface19. The door 18 is conventionally made to allow ingress and egress ofwafers, or other semiconductor work pieces or integrated circuitpackages, to be processed within the chamber 10. A gas port 20 and avacuum port 22 are provided through a surface 12 of the door 18, asshown in FIG. 2. In addition, a guiding mechanism, specifically aplurality of chamfers 15, FIG. 3, are located on an inner surface of theside 14 of the chamber 10.

As noted above, in inductively coupled plasma systems, the inductivecoil, here coil 16, is driven at a high frequency using a radiofrequency (RF) supply 27. Together, the coil and the radio frequencysupply provide a source of power for the plasma generation. As shown inFIGS. 1, 3, a wafer, or RF, chuck 26 is provided through the undersurface 19 of the chamber 10. The RF supply 27, in electrical connectionto the chuck 26, drives the coil 16 at a high frequency, therebyproviding the source of power for the plasma generation within thechamber 10.

With further reference to FIG. 3, which is a cross-sectional view thathas been elongated for clarity of description of the invention, aremovable container, or liner, 30 is encased within the processingchamber 10. The generally cylindrical container 30 has a base 32, anupper surface 34, and a side 36. The upper surface 34 acts as a door foringress and egress for a work piece, which is illustrated as a reticule50. It is, however, to be understood that any type of semiconductor workpiece may be used with the container 30, such as wafers, lead frames, orintegrated circuit packages. The chuck 26 extends through the base 32,thereby placing a top surface of the chuck 26 (upon which a work pieceto be processed will rest) within the chamber 30.

The container 30 may be formed of any suitable material which is able towithstand the environment within the processing chamber 10 for at leastas long as the processing step. For example, if a conductive material isnecessary, the container 30 may be formed of a conductive material.Alternatively, the container may be formed of a dielectric material, apartially conducting material, an insulative material, or a combinationof these. Additionally, the container 30 may be formed of a materialwhich would allow it to be subjected to more than one processing of awork piece, prior to being cleaned or discarded.

The upper surface 34 of the container 30 includes a gas port 38 and avacuum port 40. The ports 38, 40 align with the processing chamber ports20, 22 when the container 30 is positioned within the processing chamber10.

As shown in FIGS. 1-3, a gas conduit 60 extends from the port 20 of thechamber 10. It is important that the gas ports 20 and 38 closely align.Port 20 is in sealing and fluid communication with the port 38 of thecontainer 30. Further, a vacuum conduit 70 extends from the port 22 ofthe chamber 10. It is somewhat less important for the vacuum ports 22,40 to closely align. While close alignment of the vacuum ports 22, 40may be preferable, exerting a high speed vacuum in a closed system (thechamber 10) will pump the gas out of the container 30 even if the ports22, 40 are not closely aligned. As shown in FIG. 3, the port 22 isclosely aligned to the port 40 of the container 30. Compliant sealingmembers 62 and 72 are placed between the container 30 and processingchamber 10 in a space 82 and around the ports 20, 38 and 22, 40,respectively, to provide a seal preventing fluids which pass through theports from escaping into the space 82 between the container 30 and theprocessing chamber 10. The conduits 60, 70 may be pipes, hoses, or anyother suitable member defining an interior space.

Alternatively, with reference to FIG. 6, the gas conduit 60 and vacuumconduit 70 may only extend into the upper surface 34 of the container30. A mating gas conduit 60′ is fit within the port 38 and is adapted tomate with the conduit 60. The sealing member 62 is placed in position toseal the junction between the conduits 60 and 60′. A mating vacuumconduit 70′ is fit within the port 40 and is adapted to mate with thevacuum conduit 70. The sealing member 72 is placed in position to sealthe junction between the conduits 70 and 70′. The compliant sealingmembers 62, 72 may be any suitable seal, such as an O-ring or hoseclamp. Further, the sealing members 62, 72 may not be separate sealingdevices, but instead may be devices built into the hoses. For example,sealing member 62 may be a push-fit seal positioned at an end of theconduit 60 such that the conduits 60 and 60′ may mate with and be sealedtogether through pushing the conduit 60′ into the sealing member 62.

With reference to FIGS. 7, 8, the container 30 is shown with anotheraspect of the invention. To more symmetrically pump the gas andnon-volatile reaction products, and thereby more efficiently clean theinterior of the container 30, a plurality of vacuum ports 40′ arelocated on the upper surface 34 of the container 30. The ports 40′spread out the vacuuming throughout the space 80 within the container30. Thus, a more even vacuuming of the space 80 may be accomplished. Thevacuum conduit 70 should be of sufficient size to encircle all of theports 40′. As illustrated, the vacuum conduit 70 is not sealed to theupper surface 34 around the ports 40′. Alternatively, the vacuum conduit70 may be sealed to the upper surface 34.

It is required that gas pumping, or vacuuming, speeds must be relativelyhigh, and thus, it is necessary to provide a sufficiently large openingthrough which to pump the gas. Preferably, the conduit 70 should bebetween six and twenty inches in diameter. The ports 40′, as shown inFIGS. 7, should number between ten to twenty ports, each being between0.02 and 0.04 inches in diameter. Contrarily, the size of a single gasconduit 60 need not be as large as the vacuum conduit 70. Preferably,the diameter of a single gas conduit 60 should be in the range of about0.4 inches. The gas may be injected into the container 30 through asingle gas port 38, as shown in FIG. 3, or alternatively, the gas may beinjected through a multiple of smaller gas ports, much like the multipleports 40′ shown in FIGS. 7. The multiple gas ports, typically called agas distribution system or a gas showerhead, may be used to obtaingreater uniformity of gas distribution within the container 30.

The container 30 may be manually placed within the chamber 10. Thechamfers 15, which have an increasing radial height in a direction fromthe upper surface 34 to the under surface 36, assist in aligning thecontainer 30 properly within the chamber. Robotic systems may be used tomechanically place the container 30 in the chamber 10. Examples ofsuitable robotic systems include those having robot arms which arepre-aligned during maintenance and those having robot arms which areself-aligning. An important aspect of the container 30 is that itprotects the wafer or reticule 50 from particles contamination causedduring insertion of the container 30 within the chamber 10, such as, forexample, by striking one of the chamfers 15.

Next will be described an alternative embodiment of the chamber 10 andthe container 30 whereby they are supported horizontally. FIG. 9 shows ahorizontal processing chamber 310 and a container 330; specifically,lying on a chamber side 314 and a container side 336 with a door 318, anunder surface 319, an upper surface 334 and a base 332 all in avertically directed plane. The wafer chuck 326 and the RF supply 27 arepositioned under the side 314 of the chamber 310, and inductive coils316 are positioned above the chuck 326 on the top side of the side 314.The reticule 50 is positioned above the chuck 326 when the container 330is placed within the chamber 310.

A locking apparatus which releasably locks the container 330 to thechamber 310 is shown in FIGS. 9, 10. The locking mechanism includes ahole 323 provided through the chamber side 314 and a recess 342 providedin the container side 336. A biased locking pin 55 passes through thehole 323. The pin 55 is spring loaded and biased upwardly toward therecess 342. Further, the pin 55 has a rounded head 56 to facilitatelocking. Alternatively, the pin 55 may have a tapered or angled head 56.As the container 330 is placed in the chamber 310, the container side336 slides along the chamber side 314. Alternatively, this embodimentmay include the chamfers 15, in which case the container side 336 wouldslide along the chamfers 15. When a portion of the container side 336reaches the pin 55, it presses the pin 55 downwardly against the biasingforce. When the recess 342 reaches the locking pin 55, the pressurepushing the pin 55 downwardly is released, allowing the pin 55 to moveupwardly into the recess 342, thereby locking the container 330 intoplace within the chamber 310. The pin 55 may be pulled down manually, orby other means, to later unlock and release the container 330 from thechamber side 314. The recess 342 can be formed of a sufficient length toensure that the recess 342 meets up with the pin 55.

Although the apparatus for locking the container 330 to the chamber 310is shown as a spring-loaded locking pin 55 and a recess 342, it is to beunderstood that the container 330 may be locked into position within thechamber 310 in a variety of different ways. Further, although thelocking mechanism has been described in terms of the FIG. 9 embodiment,it is to be understood that the locking mechanism may be included in theembodiments shown in FIGS. 3, 6, 8, 11, and 12.

Next will be described the operation of the container 30 (FIG. 3) withinthe chamber 10. The reticule 50 is placed within the container 30, thelatter of which is guided into place within the chamber 10 by thechamfers 15. The gas conduit 60 and the vacuum conduit 70 each extendthrough the container 30 and are sealed thereto with, respectively, thesealing members 62, 72. Alternatively, the gas and vacuum conduits 60,70 are mated with, respectively, the conduits 60′, 70′, and sealedtogether with the sealing members 62, 72. Gas is introduced to a space80 within the container 30 through the gas conduit 60. Pressure withinthe container 30 may be equalized to the pressure in the space 82through a plurality of pores 44 in a side 36 of the container 30. The RFsupply 27 then drives the inductive coil 16. The amplitude of the RFsignal from the RF supply 27 needs to be sufficiently high to interactand breakdown the gas, which acts as the plasma source material. Thus,the type of gas will have a bearing upon the amplitude of the RF signalnecessary from the RF supply 27. The manner of creating a plasma,including the necessary gas compositions and RF voltages needed fordesired processing conditions are well known in the art and are notdescribed in detail herein.

As the plasma generated species react in the space 80 with the materialson the reticule 50, the vacuum introduced to the container 30 throughthe vacuum conduit 70 pulls volatile reaction products from thecontainer 30. The build up of non-volatile reaction products will occuron the interior walls of the container 30.

By utilizing the container 30, less defects are deposited on the workpiece during the processing. Further, the chamber 10 is not exposed toas many contaminant particles during the processing. Thus, the chamber10 need not be wet cleaned as frequently, thus eliminating many of there-qualifications of the chamber 10. The container 30 itself, providedit is in a good condition to be utilized again after the processing, maybe cleaned and/or refurbished and used again. Otherwise, the container30 may be discarded.

FIG. 11 shows another preferred embodiment of the present invention. Achamber 100 and a container 130 are shown in FIG. 11. The chamber 100 isgenerally cylindrical and includes an upper section 101 having a domeportion 102, and the generally cylindrical container 130 likewiseincludes a dome portion 132 which fits within the dome portion 102. Theupper section 101 of the chamber 100 may be lowered onto and secured toa lower section 103 after the container 130 is placed inside the chamber100. A space 180 is located within the dome portion 132 and in the upperreaches of the rectangular portion of the container 130. The space 180denotes an area within the container, like space 80, within which plasmaproducts are formed through a reaction between the RF signal from the RFsupply 27, the inductive coil 16 and the gas, which is introducedthrough the gas conduits 60. Vacuum conduits 70 are positioned at alower position of the chamber 130. As with previously discussedembodiments, the conduits 60, 70 may mate with conduits 60′, 70′,respectively, and be sealed with sealing members 62, 72. The container130 may be guided into the chamber 100 through a guiding mechanism, suchas the previously described chamfers 15, or any other suitable guidingmechanism. The chamber 100 and the container 130 may be supportedhorizontally or vertically, and a releasable locking mechanism, such asthe locking pin 55, may be utilized to lock the container 130 into placewithin the chamber 100.

Another preferred embodiment of the present invention is shown in FIG.12. Here, a dome-shaped processing chamber 200 is shown encasing adome-shaped removable container 230. The chamber 200 is amicrowave-generated plasma chamber. Alternatively, it may be an electroncyclotron resonance chamber. The chamber 200 is grounded by a pair ofgrounding plates 90.

Unlike inductively coupled plasma chambers, such as chambers 10, 100,the chamber 200 does not utilize a coil in conjunction with an RF supplyto produce plasma. Instead, the microwaves 216, from a microwave powersource 218 shown schematically, provide power to generate plasma withina space 280 within the container 230. The microwave power source 218 maybe any suitable source, such as, for example, a magnetron. In thisembodiment, the container 230 is preferably formed of a dielectricmaterial. The chamber 200 includes a top portion 201 which is detachablefrom and securable to a bottom portion 203. The top portion 201 isremoved, allowing the container 230 to be placed within the chamber 200.

Modifications can be made to the invention and equivalents substitutedfor described and illustrated structures without departing from thespirit or scope of the invention. For example, although the container 30has been discussed in terms of diode processing reactors, or chambers,it is to be understood that the container 30 may be used with triodereactors or any other form of chamber used to process semiconductor workpieces. Further, while certain methods of plasma generation have beendiscussed herein, such as inductively coupled plasma, electron cyclotronresonance, and microwave, other methods of plasma generation may beutilized in the invention, such as, for example, parallel plate etchers,diodes, magnetically enhanced reactive ion etching (MERIE), and surfacewave plasma. Additionally, although two ports are shown for processing aplasma, more or less ports may be used depending on the type ofprocessing which needs to be done. Further, although conduits 60, 60′,70, and 70′ have been described for pumping gas in and out of thecontainer 30, it is to be understood that other apparatus may be used,such as, for example, a plate having a plurality of openings positionedon a wall of the container 30 which is mated to a conduit. Accordingly,the scope of the present invention is not to be considered as limited bythe specifics of the particular structure which have been described andillustrated, but is only limited by the scope of the appended claims.

What is claimed as new and desired to be protected by Letters Patent ofthe United States is:
 1. A container for use with a work piece plasmaprocessing chamber, said container comprising: a housing defining anenclosed space within which a work piece can be mounted and processed,said housing including a door for access to said enclosed space and areleasable locking mechanism for releasably locking said containerwithin processing chamber, said housing having a configuration whichpermits said housing to be inserted into and removed from a work pieceprocessing chamber; and at least a pair of ports provided in saidhousing, one said port adapted to communicate fluids into the containerused in processing a work piece and at least one other said port adaptedto communicate fluids out of the container.
 2. The container of claim 1,further comprising: a gas conduit positioned through and sealed to onesaid port; and a vacuum conduit in fluid communication with said atleast one other said port.
 3. The container of claim 1, wherein saidlocking mechanism comprises a recess.
 4. The container of claim 1,wherein the container is made of materials allowing the container tohave an effective life longer than a single plasma processing.
 5. Thecontainer of claim 1, wherein the container is made of materialsallowing the container to have an effective life at least as long as theplasma processing.